Known material handling machines such as excavators have a material handling arm assembly. The arm assembly may have an arm, known as a boom, pivotally mounted about a generally horizontal axis relative to a chassis of the machine. A further arm, known as a dipper, may be attached to an end of the boom remote from the chassis and may be pivotable about a generally horizontal axis. A material handling implement such as a bucket may be pivotably mounted on an end of the dipper. The boom may be raised and lowered by operation of a first hydraulic ram. The dipper may be moveable relative to the boom by operation of a second hydraulic ram, the bucket may be moveable relative to the dipper by operation of a third hydraulic ram.
In order to handle material, for example dig a trench, a machine operator must simultaneously operate all three hydraulic actuators and this is a skillful process. A skillful operator, when digging a trench, will quickly be able to fill the bucket with material, lift bucket out of the trench and empty the bucket to one or other side of the vehicle. This excavation cycle time or loading cycle time is markedly affected by the initial penetration of the bucket into the ground. If the bucket penetrates too far into the ground then the bucket cannot be drawn through the ground to be filled. Conversely if the bucket does not penetrate far enough into the ground, then the bucket only half fills. Less well trained operators tend to operate at lower excavation/loading cycle times.
Accordingly, there is a need for an improved material handling machine.